LED display repair starter chip of 74HC595

LED display repair starter chip of 74HC595

Features and benefits

• 8-bit serial input

• 8-bit serial or parallel output

• Storage register with 3-state outputs

• Shift register with direct clear

• 100 MHz (typical) shift out frequency

• Complies with JEDEC standard no. 7A

• Input levels:

• For 74HC595: CMOS level

• For 74HCT595: TTL level

• ESD protection:

• HBM JESD22-A114F exceeds 2000 V

• MM JESD22-A115-A exceeds 200 V

• Multiple package options

• Specified from -40 °C to +85 °C and from -40 °C to +125 °C

Overview: The 74HC595 contains an 8-bit serial input, a serial/parallel shift register, and an 8-bit tri-state output latch. The register and latch have their own clock inputs (CLK and LAT), which are both rising edge active. When CLK jumps from low to high, the serial input data (SI) is shifted into the register; when LAT jumps from low to high, the register data is shifted into the latch. The low level of CLR at the clear side only resets the register. and has no effect on the latch. When the output allow control (OE) is high, the parallel output (Q0-Q7) is high resistance state, while the serial output (SO) is not affected.

Example: In led display repair.

1, OE not only controls the brightness, but also determines whether the chip is working properly premise.

2, OE is high, the chip output high resistance state, can be interpreted as uncontrolled.

3, CLK rising edge, the input signal into the chip.

4, LAT rising edge, the chip 8-bit output is normal.

5, SCLR is high, the serial data can only be lost.